Clean up the handling of template argument packs, especially in the

area of printing template arguments. The functionality changes here
are limited to cases of variadic templates that aren't yet enabled.

llvm-svn: 122250

clang/include/clang/AST/TemplateBase.h

@@ -23,6 +23,7 @@
 
 namespace llvm {
   class FoldingSetNodeID;
+  class raw_ostream;
 }
 
 namespace clang {
@@ -30,6 +31,7 @@ namespace clang {
 class Decl;
 class DiagnosticBuilder;
 class Expr;
+struct PrintingPolicy;
 class TypeSourceInfo;
 
 /// \brief Represents a template argument within a class template
@@ -280,6 +282,9 @@ public:
   /// same.
   bool structurallyEquals(const TemplateArgument &Other) const;
 
+  /// \brief Print this template argument to the given output stream.
+  void print(const PrintingPolicy &Policy, llvm::raw_ostream &Out) const;
+             
   /// \brief Used to insert TemplateArguments into FoldingSets.
   void Profile(llvm::FoldingSetNodeID &ID, ASTContext &Context) const;
 };

clang/lib/AST/ASTContext.cpp

@@ -2741,6 +2741,9 @@ ASTContext::getCanonicalTemplateArgument(const TemplateArgument &Arg) {
       return TemplateArgument(getCanonicalType(Arg.getAsType()));
 
     case TemplateArgument::Pack: {
+      if (Arg.pack_size() == 0)
+        return Arg;
+      
       TemplateArgument *CanonArgs
         = new (*this) TemplateArgument[Arg.pack_size()];
       unsigned Idx = 0;

clang/lib/AST/DumpXML.cpp

@@ -335,7 +335,10 @@ struct XMLDumper : public XMLDeclVisitor<XMLDumper>,
       break;
     }
     case TemplateArgument::Pack: {
-      // TODO
+      for (TemplateArgument::pack_iterator P = A.pack_begin(), 
+                                        PEnd = A.pack_end();
+           P != PEnd; ++P)
+        dispatch(*P);
       break;
     }
     }

clang/lib/AST/TemplateBase.cpp

@@ -12,13 +12,14 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/ADT/FoldingSet.h"
 #include "clang/AST/TemplateBase.h"
+#include "clang/AST/ASTContext.h"
 #include "clang/AST/DeclBase.h"
 #include "clang/AST/DeclTemplate.h"
 #include "clang/AST/Expr.h"
 #include "clang/AST/TypeLoc.h"
 #include "clang/Basic/Diagnostic.h"
+#include "llvm/ADT/FoldingSet.h"
 
 using namespace clang;
 
@@ -167,6 +168,69 @@ bool TemplateArgument::structurallyEquals(const TemplateArgument &Other) const {
   return false;
 }
 
+void TemplateArgument::print(const PrintingPolicy &Policy, 
+                             llvm::raw_ostream &Out) const {
+  switch (getKind()) {
+  case Null:
+    Out << "<no value>";
+    break;
+    
+  case Type: {
+    std::string TypeStr;
+    getAsType().getAsStringInternal(TypeStr, Policy);
+    Out << TypeStr;
+    break;
+  }
+    
+  case Declaration: {
+    bool Unnamed = true;
+    if (NamedDecl *ND = dyn_cast_or_null<NamedDecl>(getAsDecl())) {
+      if (ND->getDeclName()) {
+        Unnamed = false;
+        Out << ND->getNameAsString();
+      }
+    }
+    
+    if (Unnamed) {
+      Out << "<anonymous>";
+    }
+    break;
+  }
+    
+  case Template: {
+    getAsTemplate().print(Out, Policy);
+    break;
+  }
+    
+  case Integral: {
+    Out << getAsIntegral()->toString(10);
+    break;
+  }
+    
+  case Expression: {
+    // FIXME: This is non-optimal, since we're regurgitating the
+    // expression we were given.
+    getAsExpr()->printPretty(Out, 0, Policy);
+    break;
+  }
+    
+  case Pack:
+    Out << "<";
+    bool First = true;
+    for (TemplateArgument::pack_iterator P = pack_begin(), PEnd = pack_end();
+         P != PEnd; ++P) {
+      if (First)
+        First = false;
+      else
+        Out << ", ";
+      
+      P->print(Policy, Out);
+    }
+    Out << ">";
+    break;        
+  }
+}
+
 //===----------------------------------------------------------------------===//
 // TemplateArgumentLoc Implementation
 //===----------------------------------------------------------------------===//
@@ -234,9 +298,16 @@ const DiagnosticBuilder &clang::operator<<(const DiagnosticBuilder &DB,
     return DB << OS.str();
   }
       
-  case TemplateArgument::Pack:
-    // FIXME: Format arguments in a list!
-    return DB << "<parameter pack>";
+  case TemplateArgument::Pack: {
+    // FIXME: We're guessing at LangOptions!
+    llvm::SmallString<32> Str;
+    llvm::raw_svector_ostream OS(Str);
+    LangOptions LangOpts;
+    LangOpts.CPlusPlus = true;
+    PrintingPolicy Policy(LangOpts);
+    Arg.print(Policy, OS);
+    return DB << OS.str();
+  }
   }
   
   return DB;

clang/lib/AST/TypePrinter.cpp

@@ -747,44 +747,6 @@ void TypePrinter::printObjCObjectPointer(const ObjCObjectPointerType *T,
   S = ObjCQIString + S;  
 }
 
-static void printTemplateArgument(std::string &Buffer,
-                                  const TemplateArgument &Arg,
-                                  const PrintingPolicy &Policy) {
-  switch (Arg.getKind()) {
-    case TemplateArgument::Null:
-      assert(false && "Null template argument");
-      break;
-      
-    case TemplateArgument::Type:
-      Arg.getAsType().getAsStringInternal(Buffer, Policy);
-      break;
-      
-    case TemplateArgument::Declaration:
-      Buffer = cast<NamedDecl>(Arg.getAsDecl())->getNameAsString();
-      break;
-      
-    case TemplateArgument::Template: {
-      llvm::raw_string_ostream s(Buffer);
-      Arg.getAsTemplate().print(s, Policy);
-      break;
-    }
-      
-    case TemplateArgument::Integral:
-      Buffer = Arg.getAsIntegral()->toString(10, true);
-      break;
-      
-    case TemplateArgument::Expression: {
-      llvm::raw_string_ostream s(Buffer);
-      Arg.getAsExpr()->printPretty(s, 0, Policy);
-      break;
-    }
-      
-    case TemplateArgument::Pack:
-      assert(0 && "FIXME: Implement!");
-      break;
-  }
-}
-
 std::string TemplateSpecializationType::
   PrintTemplateArgumentList(const TemplateArgumentListInfo &Args,
                             const PrintingPolicy &Policy) {
@@ -806,8 +768,11 @@ TemplateSpecializationType::PrintTemplateArgumentList(
     
     // Print the argument into a string.
     std::string ArgString;
-    printTemplateArgument(ArgString, Args[Arg], Policy);
-    
+    {
+      llvm::raw_string_ostream ArgOut(ArgString);
+      Args[Arg].print(Policy, ArgOut);
+    }
+   
     // If this is the first argument and its string representation
     // begins with the global scope specifier ('::foo'), add a space
     // to avoid printing the diagraph '<:'.
@@ -840,7 +805,10 @@ PrintTemplateArgumentList(const TemplateArgumentLoc *Args, unsigned NumArgs,
     
     // Print the argument into a string.
     std::string ArgString;
-    printTemplateArgument(ArgString, Args[Arg].getArgument(), Policy);
+    {
+      llvm::raw_string_ostream ArgOut(ArgString);
+      Args[Arg].getArgument().print(Policy, ArgOut);
+    }
     
     // If this is the first argument and its string representation
     // begins with the global scope specifier ('::foo'), add a space

clang/lib/Sema/SemaTemplate.cpp

@@ -5937,91 +5937,32 @@ std::string
 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
                                       const TemplateArgument *Args,
                                       unsigned NumArgs) {
-  std::string Result;
+  llvm::SmallString<128> Str;
+  llvm::raw_svector_ostream Out(Str);
 
   if (!Params || Params->size() == 0 || NumArgs == 0)
-    return Result;
+    return std::string();
   
   for (unsigned I = 0, N = Params->size(); I != N; ++I) {
     if (I >= NumArgs)
       break;
     
     if (I == 0)
-      Result += "[with ";
+      Out << "[with ";
     else
-      Result += ", ";
+      Out << ", ";
     
     if (const IdentifierInfo *Id = Params->getParam(I)->getIdentifier()) {
-      Result += Id->getName();
+      Out << Id->getName();
     } else {
-      Result += '$';
-      Result += llvm::utostr(I);
+      Out << '$' << I;
     }
     
-    Result += " = ";
-    
-    switch (Args[I].getKind()) {
-      case TemplateArgument::Null:
-        Result += "<no value>";
-        break;
-        
-      case TemplateArgument::Type: {
-        std::string TypeStr;
-        Args[I].getAsType().getAsStringInternal(TypeStr, 
-                                                Context.PrintingPolicy);
-        Result += TypeStr;
-        break;
-      }
-        
-      case TemplateArgument::Declaration: {
-        bool Unnamed = true;
-        if (NamedDecl *ND = dyn_cast_or_null<NamedDecl>(Args[I].getAsDecl())) {
-          if (ND->getDeclName()) {
-            Unnamed = false;
-            Result += ND->getNameAsString();
-          }
-        }
-        
-        if (Unnamed) {
-          Result += "<anonymous>";
-        }
-        break;
-      }
-        
-      case TemplateArgument::Template: {
-        std::string Str;
-        llvm::raw_string_ostream OS(Str);
-        Args[I].getAsTemplate().print(OS, Context.PrintingPolicy);
-        Result += OS.str();
-        break;
-      }
-        
-      case TemplateArgument::Integral: {
-        Result += Args[I].getAsIntegral()->toString(10);
-        break;
-      }
-        
-      case TemplateArgument::Expression: {
-        // FIXME: This is non-optimal, since we're regurgitating the
-        // expression we were given.
-        std::string Str; 
-        {
-          llvm::raw_string_ostream OS(Str);
-          Args[I].getAsExpr()->printPretty(OS, Context, 0,
-                                           Context.PrintingPolicy);
-        }
-        Result += Str;
-        break;
-      }
-        
-      case TemplateArgument::Pack:
-        // FIXME: Format template argument packs
-        Result += "<template argument pack>";
-        break;        
-    }
+    Out << " = ";
+    Args[I].print(Context.PrintingPolicy, Out);
   }
-  
-  Result += ']';
-  return Result;
+
+  Out << ']';
+  return Out.str();
 }
 

clang/lib/Sema/SemaTemplateDeduction.cpp

@@ -917,6 +917,7 @@ DeduceTemplateArguments(Sema &S,
     return Sema::TDK_Success;
   }
   case TemplateArgument::Pack:
+    // FIXME: Variadic templates
     assert(0 && "FIXME: Implement!");
     break;
   }
@@ -1355,7 +1356,7 @@ getTrivialTemplateArgumentLoc(Sema &S,
     return TemplateArgumentLoc(Arg, Arg.getAsExpr());
 
   case TemplateArgument::Pack:
-    llvm_unreachable("Template parameter packs are not yet supported");
+    return TemplateArgumentLoc(Arg, TemplateArgumentLocInfo());
   }
 
   return TemplateArgumentLoc();

clang/tools/libclang/CIndex.cpp

@@ -1224,12 +1224,9 @@ bool CursorVisitor::VisitTemplateArgumentLoc(const TemplateArgumentLoc &TAL) {
   switch (TAL.getArgument().getKind()) {
   case TemplateArgument::Null:
   case TemplateArgument::Integral:
+  case TemplateArgument::Pack:
     return false;
       
-  case TemplateArgument::Pack:
-    // FIXME: Implement when variadic templates come along.
-    return false;
-
   case TemplateArgument::Type:
     if (TypeSourceInfo *TSInfo = TAL.getTypeSourceInfo())
       return Visit(TSInfo->getTypeLoc());